Air bled fuel injector system



A ril 17; 1962 Filed Oct. 26, 1951 Direction of travel of Vehicle(Upsfream) AIR H. E. BROWN BLED FUEL INJECTOR SYSTEM FIG. I. y

2 Sheets-Sheet 1 ENTOR.

HOWARD E. BROWN X10. @flw H- E. BROWN AIR BLED FUEL INJECTOR SYSTEMApril 17, 1962 2 Sheets-Sheet 2 Filed Oct. 26 1951 FIG. 4,

FIG. 3.

INVENTOR. HOWARD E. BROWN flfforney I itiffi ates ate 3,029,603 AIRBLEDFUEL INJECTOR.- SYSTEM Howard E. Brown, 'Austin, Tex., assignor .to theUnited States :ofAmerica as represented hyrthe Secretary of .1118 Navy vFiled Oct. 26, 1951,,Ser. No. 253,401 '3 Claims. '(Cl. 60---39.74)

because lateral accelerations ofthe missile caused lateral pressuregradients in'the fuel distributing headers or manifolds, whereby,inturn, some ofthe fuel nozzles received more pressure than others,resulting in non-uniform fuel feeding and consequent uneven burning.This invention is designed to prevent such maldistribution of the fuelby eliminating the header and grouping all the fuel injection nozzles atsubstantially the same location.

An object of the invention is to provide an improved construction forfeedingfuel to the burners of aramjet.

Another object of the invention is to utilize the air pressure producedby the travel of the vehicle through the atmosphere to feed air intoinjection tubes to mix with and atomize the liquid fuel that is also.fed into said tubes.

Still another object of the invention is to provide a ruggedandcompactstructure of .theair and fuel injectors and burners, wherein they arebuilt into struts extending from the inner wall of the ramjet to acentral member.

7 An additional object of the invention is to provide a fuel-injectionand burner system which has the operational characteristics of upstreaminjection even though the injection tubes may point downstream.

Other objects and many of the attendant advantages of this inventionwill be appreciated readily as the same becomes understood by referenceto the following detailed description, when considered in connectionwith the accompanying drawings, wherein:

FIG. 1 is an axial section through the burner structure of a ramjetmissile embodying the invention, with fragments of the ramjet shellsbeing shown, the section being taken along plane 11 of FIG. 2, andcertain portions being shown in elevation;

FIG. 2 is a front elevation of the burner structure for a ramjetmissile, on a smaller scale, the inner and outer shells of the ramjetbeing shown in cross section;

FIG. 3 is a cross section of a strut along plane 3-3 of FIG. 1; and

FIG. 4 is a similar cross section along the plane 4-4 of FIG. 1.

Referring first to FIGS. 1 and 2, the ramjet has an outer shell 1 and aninner shell 2, thus providing between the shells a space within whichcustomarily certain accessories may be mounted; for example, the fuelstorage tank, control mechanism, and other elements, none of which aredirectly concerned in the present invention. There is located in thisspace a fuel manifold 3 shown by way of example as a complete ring,encircling the inner shell 2, although the invention is not therebyintended to be limited to this specific form of manifold. The manifold 3is in communication with the fuel source, which may be connected theretoin any conventional way.

From the manifold 3 a fuel feed pipe 6 extends into each of the struts4, as best shown in FIG. 2. As arbilines since they are alike. fittingswell known in the art, connects the interior of manifold 3 to the fuelpassage 7 in strut 4 so that thereby liquid fuel from the storage tankwill be fed into a cenice trarily six such struts are here illustrated,therewill be the same numberof fuel feed pipes 6.

Oneof these fuel feed pipes 6 is shown in detail in FIG. 1 and it willserve to illustrate all of the fuel feed Pipe 6, by means of suitabletral cavity 8, whence it is distributed to all the burners, as describedhereinafter.

Each strut extends radially inward from the inner shell "2 to a centralhub 9'wherein a portion of said cavity'8 is located, and each strut hastherein a'fuel passage 7 communicating with the cavity, so that any orall of said pipes 6 willkeep the cavity 8 supplied with liquid fuel.

A cylindrical fitting 10 is secured to the hub 9 so that :the bore 11 ofsaid fitting forms a continuation of the cavity 8 in said hub, and has anumber of threaded openings 14 in its wall. The fitting 10, which hasaforward closed end 12, may be secured to the hub in any preferred waythat provides a tight joint, as by the slightly tapered screw threads13.

Preferably the threads in openings 14 are also tapered. For example,they may be standard pipe threads, so that a plug 15 may be tightlyscrewed into each. The plugs '15 have small axial'holes therethrough sothat .each plug may serve as a nozzle to feed liquid fuel radiallyoutward from the fitting 10. Each plug 15 may havea prismatic opening atits outer end to receive a suitable wrenchhaving acorrespondingly-shaped end, whereby the plug may be screwed into thefitting. 10. As shown, the plugs have hexagonal openings 16 to receivewrenches of the type used for socket-head screws such as the Allen typescrews.

In thefdevice specifically illustrated, there are eighteen plugs 15,three foreach of the six struts, but obviously this is arbitrary and thetotal number of plugs will vary with the number of struts and the numberper strut. Radially alined with each plug '15 is an injector passagesuch as 17, 18 and 19. Each injector passage has its inner end, such as17A, 18A, and 19A, adjacent to an annular air passage 21. The outer ends17B, 18B, and 19B of each passage 17,18, and 19 is located at 17C, 18C,and 19C of strut portion '4.

A tubular projection or cup 20 extending in the direction of travel ofthe ramjet, that is, to the left in FIG. 1, as shown by the arrow,surrounds the forward closed end 12 of fitting 10 and defines theannular air passage 21 between itself and said fitting 10. This airpassage 21 is closed at 22 at its rear end, but is in communication withthe inner end of each of the injector passages 17, 18 and 19. Theinjector passages are of unequal lengths, the forward one 17 being thelongest, the middle one 18 being somewhat shorter and the rearward one19 being the shortest.

At the outer ends of the respective injector passages are outlets 23, 24and 25, each formed between the for-. ward portion of the correspondingstrut and a separable rear portion 5.

A few additional details of the struts and the central hub are givenbelow. In order to keep the thickness of the struts small, enlargementsare provided only at their ends as shown at 26, for example, toaccommodate the threaded ends of the fuel feed pipes 6.

To keep the separable rear portions 5 in place, alining dowel pins 27,28 may be provided which will serve also to keep the inner and outerportions of the respective fuel passages 7 in proper alinement in eachstrut.

A rounded forward end portion 12 of the fitting 10 serves to diminishthe air friction at the entrance to the cup 20 and a pointed rear end 29at the center of the Patented Apr. 17, 1962 downstream side of the struthub 9 accomplishes a similar purpose there.

'In operation, assuming that the ramjet missile has been launched toproper speed, atmospheric air will flow through the inner casing 2 andsome of said air will strike the forward open end of the cup 20, andproduce stagnation pressure within the annular space 21. As a conse-'quence, air will escape radially outward through each injector passage17, 18 and 19. The fuel in cavity 8 is held at a pressure somewhathigher than the air pressure at the same time prevailing in the cup 20,so that jets of fuel will issue from the nozzles in plugs 15, directedaxially of said injector passages, thus causing the fuel to becomeatomized and mixed with the air. Finally the mixture will be dischargedthrough the laterally and rearwardly directed openings 23, 24 and 25,and burned upon reaching the air stream flowing through the ramjet.

Obviously many modifications and variations of the invention arepossible in the light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

l. A fuel distributing device for an aerial vehicle of the ramjet type,comprising a hollow hub within said ramjet vehicle, a plurality ofstruts extending outwardly from said hub to the Wall of said ramjetvehicle, said struts having passageways therein communicating with theinterior of the hub and a fuel supply manifold connected to the outerends of said passageways, said hub having a plurality of aperturesformed therein for directing fuel outwardly from the hub in jet streams,and means for receiving said jet streams and for mixing air therewithand for directing the air-fuel mixture radially to the longitudinal axisof the ramjet, whereby the flow of fuel from the hub is substantiallyunaffected by lateral accelerations of the ramjet.

2. An aerial vehicle of the fuel distributing device for a ramjet type,comprising, a hollow hub located substantially axially of said ramjetvehicle, a plurality of struts extending radially outward from said hubto the wall of said ramjet vehicle, said struts having passagewaystherein communicating with the interior of said hub and a fuel supplymanifold connected to the outer ends of said passageways, said hubhaving a plurality of apertures formed therein for directing fueloutwardly from thehnb in jet streams, and means for receiving said jetstreams and for mixing air therewith and for directing the air-fuelmixture radially to the longitudinal axis of the ramjet, whereby theflow of fuel from the hub is substantially unaffected by lateralaccelerations of the ramjet.

3. A fuel distributing device for an aerial vehicle of the ramjet type,comprising, an annular fuel man-ifold adjacent the wall of said ramjetvehicle, a centrally located hollow hub, a plurality of struts locatedbetween said hub and the wall of the ramjet, each strut being dividedinto at least two portions, a portion of each strut being integral withthe hub and extending outwardly substantially to the wall of saidramjet, the complementary portion being separable therefrom and having aconduit therein communicating with said manifold, means for holding saidhub strut portions and said complementary strut portions together toform. a rigid unit, said hub having bores therein forming continuationsof said conduits,

said hub having a plurality of apertures formed therein for directingfuel outwardly from the hub in jet streams, and means for receiving saidjet streams and for mixing air therewith and for directing the air fuelmixtures radially to the longitudinal axis of the ramjet.

References Cited in the file of this patent UNITED STATES PATENTS2,443,707 Korsgren June 22, 1948 2,499,863 Hart Mar. 7, 1950 2,529,506Lloyd et al. Nov. 14, 1950 2,568,921 .Kroon Sept. 25, 1951 2,635,426Meschino Apr. 21, 1953

